Constraints on the processing of information strongly affect behavioral decisions. In turn, these decisions influence numerous patterns of interactions between individuals and species in nature. Thus it is crucial to acquire a better understanding of the effects of limitations on information processing on behavior. The investigators use searching behavior as a model system. They propose to develop an empirical system to evaluate fundamental mechanisms and constraints underlying patterns of search for either conspicuous or cryptic food items. First, they discuss theory and evidence demonstrating (1) that the brain has a limited capacity for the amount of information it can process simultaneously, and (2) that after switching to an already familiar but difficult activity, there is a delay in either the retrieval or use of relevant information; this results in an initially lower performance after such switching. The investigators refer to the former constraint as "limited attention" and to the latter as the "cost of switching". Second, they propose experiments to (1) evaluate "natural" decisions by subjects searching for either conspicuous or cryptic targets, (2) measure effects of switching between target types on searching performance, and (3) determine how the cost of switching affects either foraging movements or choice between "food patches". This research, which integrates evolutionary theory and cognitive psychology, can have two major contributions. First, by studying how brain mechanisms affect behavior and fitness, it adds the crucial dimension of utility to the study of cognitive architecture. Second, by understanding realistic facets of information processing, it contributes explanatory models of key behaviors to evolutionary biology.